The premise of “Best of Enemies” — a movie about two intellectuals debating each other on television in 1968 — may sound like a snooze.

Yet the film is amazingly relevant, hugely entertaining, very funny, and a strong contender for 2015’s best documentary.

Opening Friday at the Clay Theatre, “Best of Enemies” is co-directed by Oscar-winner Morgan Neville (“Twenty Feet from Stardom”) and Robert Gordon, who says he tried to make the film about a series of debates on issues of the day between conservative William F. Buckley Jr. and liberal Gore Vidal — broadcast by ABC in an attempt to boost ratings — as non-partisan as possible,

Gordon began by cutting footage from the 2 1/2 hours of debates that specifically referred to events from 1968.

“What was left was the catfighting between them, and the bigger issue ideas,” he says. “It felt like they were anticipating today. These guys knew the cultural war was coming.”

Gordon gave each player equal weight. (He had the opportunity to interview Vidal before his death in 2012 — Buckley died in 2008 — but the interview did not go well, and it became clear it would upset the balance of the movie.)

Realizing that many people today aren’t familiar with Buckley and Vidal, Gordon added a biographical element; Kelsey Grammer and John Lithgow lend their voices to Buckley and Vidal’s writings.

Gordon himself needed a bit of schooling.

“I’m not ashamed to say that in the first months of this I kept a dictionary handy,” he says, adding that the debaters were “eerily parallel. Part of the reason they had so much animosity for each other is that they were so well-matched. They could each throw around ancient Roman philosophers as easily as they could battles in World War II or contemporary novelists.”

Buckley and Vidal’s passionate, educated bickering eventually culminated in an on-air explosion, which seems to have given rise to today’s empty, anti-intellectual, shock-debates on TV.

“The explosive moment is what networks came away with,” says Gordon. “They realized that people don’t want to see the fuse being lit. They don’t want to feel the tension of the moment. They just put two people in a room and prod them: Go!”

But back then, Buckley and Vidal acted from their hearts and souls. “I think they each felt like the other was going to destroy the world,” Gordon says, “and each was trying to save it.”

IF YOU GOBest of EnemiesStarring William F. Buckley Jr., Gore Vidal, Kelsey Grammer, John LithgowWritten and directed by Robert Gordon, Morgan NevilleRated RRunning time 1 hour, 27 minutes